An internal combustion engine (ICE) generally includes an air intake system having an intake manifold and an air duct for conveying fresh air from the environment into the intake manifold, an exhaust system having an exhaust manifold for collecting the exhaust gasses and directing them to an exhaust pipe that conveys the exhaust gasses to the environment, and a turbocharger having a compressor located in the air intake system for compressing the air stream flowing therein and a turbine located in the exhaust system for driving the compressor.
In order to reduce the undesirable exhaust emission, some internal combustion engines, having a turbocharger, are provided with a long route exhaust gas recirculation (EGR) system, for selectively routing back exhaust gas from the exhaust system into the air duct of the air intake system. In such a way the exhaust gas mixed with the fresh air is aspired into the engine cylinders, in order to reduce the production of nitrogen oxides (NOx) during the combustion process.
In details, long route EGR systems include an EGR pipe fluidly connecting the exhaust system downstream of an ICE particulate filter (DPF) with the air duct upstream of the compressor of the turbocharger, an EGR cooler located in the EGR pipe, and a valve for regulating the flow rate of exhaust gas through the EGR pipe.
A drawback of the long route EGR systems is due to potential water condensation in cold environmental condition. Indeed, during the engine warm up phase in cold environmental condition it happens that exhaust gas mixed with the fresh air condensates, generating water droplets which flow against the compressor wheels causing damages to the compressor of the turbocharger. Accordingly, it is desirable to prevent the condensation of the recirculated exhaust gas and thus protecting the compressor from the water droplets that can be generated that way.